Washington -LRB- CNN -RRB- -- Two FBI special agents were killed Friday during a training exercise off the coast of Virginia Beach , Virginia , the bureau said in a statement released Sunday .

`` Special Agent Christopher Lorek and Special Agent Stephen Shaw were assigned to the FBI 's Critical Incident Response Group . The cause of the incident is under review . ''

An official who asked not to be identified told CNN that the two agents were killed in a hostage rescue training exercise .

The official gave no further details .

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Two special agents died Friday in an incident during training , the FBI says

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An official says they were killed during a hostage rescue training exercise